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An acute reversible experimental model of pneumonia in pigs: time-related histological and clinical signs changes


Tomas Martin-Jimenez, Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA. E-mail:


The objective of this study was to evaluate the long-term survival rates, clinical response, and lung gross and microscopic changes in pigs treated intratracheally with lipopolysaccharide of Escherichia coli 0111:B4 (LPS-Ec). Healthy pigs were randomly allocated to three groups: (i) no-LPS-Ec (n = 1), (ii) LPS-Ec-T1 (1 mg/mL, 10 mL/pig) (n = 7), and (iii) LPS-Ec-T2 (0.5 mg/mL, 10 mL/pig) (n = 6). Two pigs from each dose group were euthanized at 24 (n = 3 for T1), 48 and 144 h post-LPS-Ec challenge. LPS-Ec-treated animals showed macroscopic lesions in middle lobes of the lung. A reversible recruitment of macrophages and neutrophils was observed at 24, 48, and 144 h post-LPS-Ec challenge. The highest cellular infiltration level was observed at 24 h after challenge. The highest clinical scores were evident in both experimental dose levels within 3 and 5 h after LPS-Ec administration. Administration of LPS-Ec, under the conditions evaluated, can be used to induce a reproducible model of acute pulmonary inflammation in pigs.